About a year ago a new initiative started to develop a comprehensive research and development program to meet the challenging demand of future transfusion services. As part of our service responsibility, we will be required to provide state-of-the-art quality supports and consultation to the other sectors within the institute. To complement our expertise and experience in viral hepatitis research, and to be selective and focused, we chose to build this new R&D program on an infectious disease model. To investigate gene therapy as a therapeutic approach for human hepatitis C infection and to develop this approach as a model for chronic infectious diseases, we have set up the following goals: (a) to establish a functionally measurable gene expression model in hematopoietic cells using a virally-mediated gene delivery system for the hepatitis C virus (HCV) gene; (b) to develop lineage-specific gene expression in hematopoietic cells for HCV genes; (c) to demonstrate the efficacy of lineage-specific gene expression by functional assessment with CTL assays and tumor-killing assays directed to HCV-specific epitopes; and, (d) to establish lineage- specific gene expression as a therapeutic modality against chronic HCV infection. In the past year, in a mouse model, we have evaluated a viral gene delivery system and established CTL assays against HCV core and envelope proteins.